Previous circuits used to provide selected voltage drops across a load resistance typically included current source circuitry having the Wilson topology which provides an output current controlled by voltage at an input terminal, as generally determined by the selection of resistor components in the topology. However, prior art the topology, such as shown in FIGS. 1 and 2 exhibits significant transistor base-emitter voltage process and temperature variation dependencies. Therefore, the applicability of the Wilson-type current source is limited to those applications wherein the process and temperature induced variations can be tolerated.